Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau treo » cau theo, cau tren, cau triet
qua cac » cua cac
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
nang xa » nang x, lang xa, nang ma
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
danh di » danh du, xanh di, danh dien
y nang » ky nang, ly nang, v nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang xa hoi. hieu qua cac luc van ((danh di) or (hanh de)) ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang xa hoi. hieu qua cac luc van ((danh di) OR (hanh de)) ((cua tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: toc sach y nang xa hoi. hieu qua cac luc van ((danh di) or (hanh de)) ((cua tre) or (cau treo))*.